1. Field of the Invention
The present invention relates to a device with a stepped adjustment for adapting the vertical position of the rolls of a roll stand to the rolling line, wherein the rolls are supported on both sides in chocks and arranged so as to be raisable and lowerable in roll housings, particularly in a four-high skin pass stand or sizing stand operated with low rolling force.
2. Description of the Related Art
For rolling technological reasons, different roll diameters have to be used in roll stands; this primarily concerns the work rolls. Different measures are known for adjusting the upper edges of the work rolls to the rolling line to ensure that the diameter differences of the rolls do not result in substantial changes of the rolling line. These measures include, for example, the placement of fitting plates selected in accordance with the required dimension of compensation, selectively moving fitting pieces of different heights received in a sliding frame under the chocks into the housing windows of a four-high stand, or wedge-type adjustments with a pair of wedges arranged under each chock of the back-up roll, as disclosed in EP 0 513 946 B1. These pairs of wedges are arranged in such a way that each upper wedge element can be raised and lowered by means of a lifting device together with the respective roll chock and the wedge surfaces of both wedges are provided with steps, wherein the steps engage into each other so as to support the wedge elements. These known step-type adjustments are very complicated and make the roll exchange very difficult.
DE 44 17 274 A1discloses rolling in the same roll stand high-strength steel qualities as well as very soft steel qualities which can also be deep-drawn well in skin passes with very small rolling forces, wherein the cumulative rolling force of at most 1,000 t is very low as compared to reducing stands. The rolling force required for the skin pass procedure is applied, after lifting a back-up roll, by the bending device of one of the remaining rolls of the roll set of the lifted back-up roll. In this stand, the rolling line adjustment by means of the conventional wedges is very complicated.